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<head><meta charset="utf-8"><title>compile speed · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/compile.20speed.html">compile speed</a></h3>

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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/compile%20speed/near/199284024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/compile.20speed.html#199284024">(May 31 2020 at 01:13)</a>:</h4>
<p>I saw <a href="https://prev.rust-lang.org/en-US/faq.html#why-is-rustc-slow">this</a> on the old Rust website (not sure if it's on the new one), and I'm wondering if it's still an issue:</p>
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<p>Secondly, the Rust compiler suffers from long-standing technical debt, and notably generates poor-quality LLVM IR which LLVM must spend time “fixing.” The addition of a new internal representation called MIR to the Rust compiler offers the potential to perform more optimizations and improve the quality of LLVM IR generated, but this work has not yet occured.</p>
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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/compile%20speed/near/199284075" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/compile.20speed.html#199284075">(May 31 2020 at 01:15)</a>:</h4>
<p>Also, is there incremental compilation <em>within</em> a crate?</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/compile%20speed/near/199284120" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/compile.20speed.html#199284120">(May 31 2020 at 01:16)</a>:</h4>
<p>MIR has been a thing for years at this point, but there is still a lot of work to do to improve the LLVM IR by doing more optimizations on MIR</p>



<a name="199284121"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/compile%20speed/near/199284121" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/compile.20speed.html#199284121">(May 31 2020 at 01:16)</a>:</h4>
<p>Same for incr. comp.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/compile%20speed/near/199284125" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/compile.20speed.html#199284125">(May 31 2020 at 01:17)</a>:</h4>
<p>It works, but can still be improved</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/compile%20speed/near/199284171" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/compile.20speed.html#199284171">(May 31 2020 at 01:18)</a>:</h4>
<p>Good to know, thanks!</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/compile%20speed/near/199293435" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Tshepang Lekhonkhobe <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/compile.20speed.html#199293435">(May 31 2020 at 06:22)</a>:</h4>
<p>sidenote: am glad that faq is kept around... it is full of gems, outdated as much of it is</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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